Radiation fans aim to generate airflow to disperse heat. They have many types depending on use environments and utilization. As the technology advances, industries such as those in information and communication progress rapidly. The demand for radiation fans used on delicate electronic products also grows significantly. The delicate electronic products require the radiation fans that have a greater power and higher rotation speed and are constructed at a smaller size to generate airflow to lower the high temperature being generated so that they can maintain desired operation efficiency within a selected temperature range. If the heat energy generated during product operation cannot be dispelled effectively, the elements could be damaged or catch fire because of excessive high temperature. The consequence could be severe. Hence most delicate electronic products are equipped with radiation fans to dispel heat.
A conventional improved radiation fan structure mainly includes a radiation fan which has radial vanes and a seat which has a rotation space to house the radiation fan. The seat has a circuit board and a coil set to receive electric power to drive the radiation fan to rotate. The radiation fan has a spindle in the center. The seat has a bearing corresponding to the spindle. In the present technique, due to the constraint of the installable size of the radiation fan, the efficiency of the radiation fan is determined by the rotation speed thereof. But during high speed rotation, excessive friction occurs between the spindle and the bearing, and high temperature is generated. As a result, the spindle easily skews and hits the bearing, and abnormal noise is generated. To remedy these problems, wearing-resistant ceramic bearings have been developed. However, the ceramic bearings have a higher hardness and are more difficult to fabricate. The problem of high temperature generated by friction also remains unsolved.